FIG. 63 shows an example of conventional LED lamp (see Patent Document 1, for example). The LED lamp X shown in the figure includes a plate-like substrate 91, a plurality of LED modules 92 mounted on the substrate 91, a heat dissipation member 95 attached to the substrate 91, a case 93 accommodating the substrate 91, and terminals 94. The substrate 91 is provided with a wiring pattern, not shown, connected to the LED modules 92 and the terminal 94. The LED lamp X is structured such that the LED modules 92 can be turned on when the terminals 94 are fitted into inlet ports of a socket of a general-use fluorescent lighting fixture.
The general-use fluorescent lighting fixture herein refers to lighting fixtures widely used for interior lighting as the main application, and more specifically, lighting fixtures which use, for example in Japan, a commercial power supply (e.g. AC 100 v) and to which a JIS C7617 straight-tube fluorescent lamp or a JIS C7618 circular fluorescent lamp can be attached. (Hereinafter, such a general-use fluorescent lighting fixture is simply referred to as a “lighting fixture”.)
When the LED lamp X is attached to a lighting fixture on e.g. an indoor ceiling, the main light emission direction of the LED modules 92 is oriented downward. When the LED modules 92 are turned on, most part of the light emitted from the LED modules 92 is directed in the main light emission direction of the LED modules 92. Thus, sufficient brightness cannot be obtained at the surrounding area of the LED lamp X, especially near the sides of the LED lamp X.
As compared with this, general-use fluorescent lamps can emit light from almost the entire surface of the case, so that the surrounding area of the lighting fixture is uniformly illuminated to obtain sufficient brightness. Thus, as compared with general-use fluorescent lamps, the LED lamp X has a disadvantage that sufficient brightness cannot be obtained especially near the sides of the lamp.
Patent Document 1: JP-U-H06-54103